Wheelchairs are available in a variety of widths, generally intended to accommodate a variety of users depending both on the user's size, as well as on the manner in which the wheelchair is used. The needs of someone permanently confined to a wheelchair differ greatly from someone who is using a wheelchair during rehabilitation or recuperation. For example, healthy but impaired people may prefer to have a sports model of a chair with a tighter seating fit. in accordance with the prior art, issues of fit have been complicated by the fact that the wheelchair base, including the seat base and vertical post width come in standard incremental sizes. Accordingly, despite complex inventory issues, wheelchair backs have been provided in incremental sizes intended to accommodate the nearest incremental size chair base. The present invention answers the deficiencies of this system by providing a back, which has incrementally or infinitely adjustability to accommodate a range of standard size chairs and provide for the specific requirements of a variety of users.
As a further aspect of the invention, the back assembly provides multiple options with respect to the adjustability relative to the seat and yet which is easily installed and used. Thus, the back assembly mounts on the vertical post or cane of a wheelchair and can be adjusted up and down, in and out, and at various angles relative to the seat.
Finally, as a separate aspect of the invention, a back assembly system is provided which allows for a variety of support functions including separately from thoracic support, sacral support, support for the lateral regions of the shoulders, and head support. Means are provided to give adjustable lateral support, which can be varied independently one side of the other, and also according to the angle of the desired support. Thus, in accordance with the invention, a back assembly is provided which generally comprises a base member, mounting hardware, and optionally one or more lateral stabilizers. The base member consists of one or more rigid shells covered with a compressible foam. In the event that multiple shells are used, connecting means are used such as a locking hinge. The mounting hardware includes a first transverse member, which can be adjusted relative to the shell to accommodate varying widths of wheelchair frames. A second member can be adjusted in and out in depth. A pin is attached to the second member and allows the assembly to be pivoted around a transverse axle relative to the clamp in order to provide for a variety of angles of the back. Clamping members are releasably secured to the pin. Finally, the first and second members includes means to provide for incremental adjustment such as for example mating arm members which can have a scalloped camming surface so as to slide into incremental positions of adjustment. In an alternative embodiment, the second member has a sliding connection relative to the first member which may, for example, be provided by a keyway?? or dovetail which allows for longitudinal adjustment while retaining a connection between the members.
The back member comprises at least one rigid shell which would constitute a thoracic support but can optionally include additional shells such as a single sacral support, or double lateral sacral supports, corresponding single or double shoulder supports, and a head rest portion. The components may be jointed using a locking hinge, which is easily adjusted into a locked position. The back member is covered with a compressible foam and an outer covering.
Lateral support members (which may be shallow or deep) are provided which can be adjusted in and out and at various angles relative to the back member. A foam covering system is provided which accommodates adjustment of the lateral members relative to the back.